Some species have become problematic invasive species in Africa, Asia, and Australia. Mesquites are also often regarded as "invasive" pests within their native range on
rangelands of the
Southwestern United States.
In its native range In the United States, native mesquites have increased in abundance and become the dominant woody plant on of semiarid grasslands. Their recent success is mostly attributed to the introduction of domestic livestock, although other factors include climate change,
overgrazing, and the reduction of fire frequency. In Mexico and the US, the two most problematic species are Eastern honey mesquite (
Neltuma glandulosa) and velvet mesquite (
Neltuma velutina). and have dense stands reported to suppress the majority of grass production. In some cases, they have been able to successfully outcompete the native
Prosopis species. Additionally
N. laevigata was previously invasive in Australia, but has since been eradicated. The last known specimens of
N. laevigata were eliminated in 2006, but given the possibility of lingering seeds in the
soil seed bank,
Biosecurity Queensland waited 15 years and declared Australia free of
N. laevigata in 2021. In
India, mesquites had been introduced decades ago, but until recently, their effects had not been studied. This genus has been pushing out the
Indian wild ass (
Equus hemionus khur). This herbivorous mammal eats the pods of mesquites, which was one of the intended purposes of its introduction. Through digesting and excreting the seeds, the Indian wild asses are providing the habitat needed for germination. The
Indian Wild Ass Sanctuary is experiencing mesquite invasion of roughly a year. By overtaking the land, the dense canopy cover of mesquite has made it so native vegetation cannot grow. It has also made watering holes inaccessible to the animals within this region. This lack of resources and range is forcing the endangered Indian wild ass into human landscapes and agriculture fields and locals are killing these asses to protect their crops.
Control strategies Controlling mesquite is a challenging task. One often-used method is mechanical control. This can be effective with high mortality rates if stems are cut at least underground. Another method is through the application of herbicides, done on an individual plant basis. Basal application is effective to mesquite of all sizes, while foliar application is best for plants smaller than . Another physical option for control is through fires. Some species of mesquite are fire-sensitive, while others are fire-tolerant. For those that are fire-sensitive, this method can be highly effective, but those that are fire-tolerant require hot and intense fires to be effective. In Australia, scientists are trying biological control methods. They have introduced multiple insects, but the most effective in causing high population level impact is the leaf-tying moth (
Evippe spp.). The most recommended method for managing mesquites, both in native and introduced ranges, is by targeting large numbers of plants either through herbicide or physical removal. Also, research is being done on using satellite and aerial images to assess canopy cover and determine which ranges should be targeted. ==Species==